Galaxy 2014 developed an intermittent failure of the cruise control to turn on and more recently also the speed limiter.

When it turned on it worked flawlessly, and it worked best in warm weather, indicating a poor connection somewhere.

The steering wheel mounted switches were a clear favourite for the fault and I found a website suggesting spraying switch lube into the square gaps behind the switch face plate. Tried that and no change. 

I also checked fuses, the brake and clutch pedal switches but this was unlikely as it did work once on.

Finally I was going to remove the air bag and check the connections behind the steering wheel and the "clock spring" as this is apparently a known fault.

However, I adjusted the rake on the steering wheel to gain better access and immediately the cruise and speed limiter were working perfectly.

Loose connection confirmed, just need to find the exact spot and repair it.

Hope this helps.

Did you ever get to the root of the problem? My 2015 is doing exactly the same thing.

Hello @Attila1959 you are not going to get a reply from @dotbear who is yet another "One Post Wonder" made a post on 23 January 2020 and never returned.

If you really want to find out why your cruise is not working you need to get a laptop and download the software FORScan. You will also need a vLinker FS connection lead.

Then you connect up to your cars OBDII port and check the status of the 40 plus things that have to be correct before cruise control can be switched on.